The disclosed embodiments relate generally to an improvement for a printing system (employing an interposer or inserter) and, more particularly, to a system and method for reducing print delays with respect to “mixed” print jobs.
The primary output product of a typical printing machine is a printed substrate, such as a sheet of paper bearing printed information in a specified format. Quite often, customer requirements necessitate that this output product be configured in various specialized arrangements or print sets ranging from stacks of collated loose printed sheets to tabulated and bound booklets. Even when using state of the art document producing and finishing apparatus, it may be necessary to insert sheets into the document which are produced by means other than the document producing apparatus, or produced at a separate time from the majority of the sheets contained in the print set. For example, it is not uncommon to place specially colored sheets, chapter dividers, photographs or other special insert sheets into a print set to produce a final document. Additionally, it is not uncommon to use preprinted sheets which were produced by four-color offset press techniques as special insert sheets in a document containing mostly text printed on ordinary white paper. In another example, booklets produced from signatures, often use special cover sheets or center sheets containing, for example, coupons. It is generally not desirable to pass these sheets through the printer processing apparatus because the ink on the special insert sheets tends to be smudged by the paper-handling rollers, etc. of the document producing apparatus. In addition, these special insert sheets may be of a particular weight stock or may include protruding tabs which may cause jams when transported through the printer processor. Different sheets of a single document may require different machine setup, e.g. fuser roll, fuser temperature, Xerographic settings, Xerographic inks etc, which require a certain time to change from one setting to another.
Accordingly, these special insert sheets must be inserted into the stream of sheets subsequent to processing in the printer processor section of the document producing apparatus. It is desirable to insert these sheets without disrupting the flow of the continuous stream of processed sheets. It is also desirable to insert these sheets in a manner which is transparent to the print processor or the finishing apparatus so that the operation of these apparatus need not be modified. A printing system with an interposer or inserter is disclosed in U.S. Pat. No. 5,596,389 to Dumas et al., the pertinent portions of which are incorporated herein by reference. Referring to column 1, line 51 through column 3, line 31 of U.S. Pat. No. 5,596,389, brief descriptions of disclosures relating to the area of inserting one or more insert sheets among a plurality of previously marked sheets are provided.
In various known printing systems, marking software is employed, in conjunction with one or more controllers, to implement a sheet scheduling technique. More particularly, in one known system each page of a job is programmed for printing and the corresponding marking related information is communicated to a print manager node. In turn, the print manager node generates a schedule indicating the sequence in which the sides of the job pages are to be printed. The functionality of some possibly applicable marking software is described in U.S. Pat. No. 5,535,312 to Hammer et al., the pertinent portions of which are incorporated herein by reference. As discussed in U.S. Pat. No. 5,535,312, with the marking software, the time at which each stored image is to be fed to a photoreceptor may be designated in a list or table, in advance of marking. As printing proceeds, the scheduling controller refers to the list or table for determining which image should be fetched from disk; and transmitted to the system memory for processing by one of the image generator processors. During the scheduling process a scheduling controller may generate gaps (defined by one or more unused pitches) between a set or a job. Moreover, pitches may be intentionally scheduled within the printing of a single set. For example, as discussed in U.S. Pat. No. 5,159,395, the pertinent portions of which are incorporated herein by reference, in one mode of operation a pitch is interleaved between two adjacent sheets on the photoreceptor to facilitate the finishing of multiple sets produced from a stored job.
Under certain circumstances, a job may include a varying attribute (e.g., where multiple media weights are employed). When this occurs, operational accommodations may be required for purposes of obtaining appropriate marking. For instance, when printing booklets with covers (where the print media associated with each cover is heavier than the print media associated with the other pages of the booklets), the temperature of the fuser may be greater for the cover than the other pages. Switching between print media to accommodate for change in fuser temperature can cause the print engine to skip pitches. This can dramatically reduce printing speed of the printing machine, and result in print delays.
There are numerous other scenarios in which a varying attribute for a print job (such as varying media weight, varying media size, varying media color, and varying plex) may be encountered. For instance, a job may require the marking of both monochrome and color prints. It is understood that printing one or more color prints in the middle of printing a predominately monochrome job can lead to print delays. An example in which color prints are interposed with monochrome prints is disclosed in a Xerox Disclosure Journal article to P. F. Morgan (vol. 16, No. 6, November/December 1991) entitled Integration of Black Only and Color Printers (“XDJ Article”). While the XDJ Article teaches that the preprinted color prints may be automatically inserted into a monochrome based hardcopy print stream, it is not believed that the XDJ Article discloses, teaches or suggests an approach for automatically processing a mixed color print job from an input end of a printing machine (e.g., digital front end) to an output end of the printing machine (e.g., post fuser output collection area).
In accordance with one aspect of disclosed embodiments there is disclosed a printing system for producing a print job. The printing system includes: A. a controller for receiving an electronic document represented by an original stream, the original stream including at least two printing related instructions, said controller (1) reading the at least two printing related instructions, and (2) responsive to said A(1), segregating the original stream into two or more streams; B. a printer for processing one or more of the two or more streams to produce one or more sets of prints; C. one or more inserters, the one or more sets of prints resulting from the printing of B being automatically stored in said one or more inserters; D. said printer, subsequent to said storing in C, printing another one of the two or more streams to produce a final set of prints corresponding with a hardcopy print stream having at least one gap, the at least one gap in the hardcopy print stream being disposed between a leading edge of one print and a lagging edge of another print; and E. pursuant to the printing of D, using said one or more inserters, in conjunction with said controller, to automatically insert at least one print of the one or more sets of prints into the at least one gap in the hardcopy print stream to produce the print job.
In accordance with another aspect of the disclosed embodiment there is disclosed a method of producing a print job in a printing system. The method includes A. receiving an electronic document represented by an original stream, the original stream including at least two printing related instructions; B. reading the at least two printing related instructions; C. responsive to said B, segregating at least part of the original stream into two or more streams; D. printing one or more of the two or more streams to produce one or more sets of prints; E. automatically storing the one or more sets of prints resulting from said D; F. printing another one of the two or more streams to produce a final set of prints; and G. pursuant to said F, automatically combining the one or more sets of prints with the final set of prints to produce the print job.